Sputtering at 1-3k RPM??

[topgunsnsx]

After the car has fully warmed up and been driven for a while. If I stop the engine for 0-30 or so minutes, then try to restart it and drive the car it will sputter and hesitate below 3k RPM. I can feel the sputtering, but if I keep gasing it the car will get past the hesitation and continue going. After 3k RPM, this all stop and the car runs fine. On a couple of occasion the hesitation has been bad enough to get the CEL light blinking for a few seconds. The CEL usually stops blinking and the car is fine after that. After a minute or so of driving, no more hesitation and car runs fine. This only happens after a warm restart. Every morning I start the car when cold and never have this problem. I've already clearned Intake, changed sparks plugs and O2 sensors. What can be the issue? Thank you.

 

[BATMANs]

I had something similar on another car.

Ran redline SI-1 injector cleaner and problem solved.........

 

[topgunsnsx]

I had something similar on another car.

Ran redline SI-1 injector cleaner and problem solved.........

I've been using Techron FI cleaner and Chevron gas on a regular basis, wouldn't this do the same as Redline?

 

[goldNSX]

As you said you've changed the 02 sensors...did you pull the code?

 

[Olyar15]

I believe that the flashing CEL indicates a severe misfire. You might be running rich, or maybe bad spark plugs. I would check your plugs for a start.

 

[topgunsnsx]

As you said you've changed the 02 sensors...did you pull the code?

I pulled the bad O2 codes a few months ago and changed both front primary ones already.

 

[topgunsnsx]

I believe that the flashing CEL indicates a severe misfire. You might be running rich, or maybe bad spark plugs. I would check your plugs for a start.

Plugs are only 4-5 months old and I've already rechecked them. They still look great. Yes, when the CEL flashes I can feel the car sputtering. If I just stomp on the gas pedal some, it'll stop sputtering and the CEL will stop blinking. If I start the car and firmly press on the gas pedal more to drive the car at a higher then 3k RPM, there doesn't seem to be this sputtering issue. Thanks for your input.

 

[goldNSX]

I pulled the bad O2 codes a few months ago and changed both front primary ones already.

Well, sorry for asking again but what is the code NOW?

 

[BATMANs]

I've been using Techron FI cleaner and Chevron gas on a regular basis, wouldn't this do the same as Redline?

it's not as good.

I know that RX7 and Supra guys avoid Chevron gas since there is something in there that makes it more likely to detonate.

If u live in the bay area look for "Clean Power" 2 bottles will clean up ur entire fuel line.

It's even save one of my O2 sensors on the truck when my CEL indicated that it was toast.

 

[topgunsnsx]

Well, sorry for asking again but what is the code NOW?

P0152 and P0155 I believe, which points to the Front primary O2 sensor. I changed out both primary O2.

 

[NSXclear]

I had the exact same hesitation problem.

Check the fuel pressure. It might be a bad fuel pump. Make sure it is within the Service Manual specs.

I got both O2 sensor MIL/CEL lights also, but the O2 sensors hardly go bad at the same time, especially after you replaced them.

Once I replaced the fuel pump, no more light and no more hesitation.

To get to the fuel pump, you will have to drop the fuel tank. Make sure you drive your car and get the gas low as possible. Disconnect your battery. Remove your fuel fill cap. Remove the fuel relief bango bolt on the fuel filter. Then drain out the remaining gas through the drain bolt. Getting off the fuel hose can be a PITA. Remove a couple of braces and straps that are in the way of the fuel tank underneath.

You should either go with the stock fuel pump $350.00 or go with the walbro fuel pump with NSX kit for around $99.00. I went with the walbro option in case I go FI.

 

[topgunsnsx]

I had the exact same hesitation problem.

Check the fuel pressure. It might be a bad fuel pump. Make sure it is within the Service Manual specs.

I got both O2 sensor MIL/CEL lights also, but the O2 sensors hardly go bad at the same time, especially after you replaced them.

Once I replaced the fuel pump, no more light and no more hesitation.

To get to the fuel pump, you will have to drop the fuel tank. Make sure you drive your car and get the gas low as possible. Disconnect your battery. Remove your fuel fill cap. Remove the fuel relief bango bolt on the fuel filter. Then drain out the remaining gas through the drain bolt. Getting off the fuel hose can be a PITA. Remove a couple of braces and straps that are in the way of the fuel tank underneath.

You should either go with the stock fuel pump $350.00 or go with the walbro fuel pump with NSX kit for around $99.00. I went with the walbro option in case I go FI.

I'll check that out. Thanks.

 

[goldNSX]

If you don't have a fuel pressure gauge you can short the resistor cable and see if the hesitation below 4k rpm goes away.

 

[pgilliam1]

If I recall correctly, the NSX has a 2 stage fuel pump. 1st stage at low RPM and then 2nd stage kicks in at higher RPM. Sounds like your problem to me. As said - check fuel pressure at idle.

 

[topgunsnsx]

If you don't have a fuel pressure gauge you can short the resistor cable and see if the hesitation below 4k rpm goes away.

Please be specific, what cable are you referring to. The more details you can give the better, pictures would be great also. Thank you.

 

[goldNSX]

Please be specific, what cable are you referring to. The more details you can give the better, pictures would be great also. Thank you.

I can't find my pic on prime. It's in the engine compartment, passenger side, above the fuel filter, alu ripped cigarette size box (yes, I'm a smoker :tongue. Disconnect the cable, short it savely and go for a drive. Safely means: if it looses connection you lose power...
If the car pulls much better below 4k rpm your fuel pump is bad/old. Have a look in the SM for the correct location of the FPResistor if you are unsure.

pgilliam1 is right and this is what I was referring to. Above 4k stage II begins. With shorting the cable you are always in stage II, at low and high rpm's. If your symptom goes away, your fuel pump delivers not the required amount of fuel in stage I.

Good luck!

BTW: I had some very seldom hesitation for about 2 years, changed some parts but didn't succeed. I was always wondering why any stock NSX pulled more below 4k rpm while mine has some upgrades which seemed to have slowed the car down. After the test I knew why.

Let us know.

 

[NSXclear]

You can borrow a fuel pressure guage at Autozone, if you don't already have one.

 

[NSX~PERT]

My car is doing the same hesitation for years now but it would do it evry once in awhile sometimes I get in the car it would be fine and then get to a destination let the car cool down then start up again and it would hesitate.

Now I'm FI changed out injectors, fuel pump, new spark plugs, new AEM O2 sensor so pretty much eliminated all the issues I thought it could be and it did it to me again last night

One thing I considered but havent been able to check is possibly a bad coil? Any help would be great. How can I check the coils? If thet can be a cause

 

[BATMANs]

I'm sputtering and misfiring intermittently at all RPMs.

I'm thinking it's the plugs and coils.